Silas e



UNITED STATES PATENT GFFICE.

SILAS E. SELLEOK, OF WEST TROY, NEW YORK.

TRAMMEL.

SPECIFICATION forming part'of Letters Patent No. 472,829, dated April 12, 1892.

Application filed August 28, 1891. Serial No. 404,011, (No model.)

hereby declare that the following is a full,

clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in trammels or beam-compasses, the object be- 1 designates the beam, which maybe provided with a-graduated scale, as usual.

2 and 3 designate the tramrnel-heads, which are movable upon the beam. These heads are provided with spring-blocks i in their upper ends and set-screws 5, pressing upon said blocks, so as to securely hold the heads in place on the beam in the'ordinary manner.

Depending from the under side of tram- -mel-head 2 is an arm 6, having an outwardlyprojecting lug 7 upon each side of the lower end thereof.

The numeral 8 designates the trammelpoint secured to the plate 9. This plate is recessed at one end, forming two shoulders 10, which engage with the lugs 7 when the arm 6 is placed in the recess in plate 9, which it is adapted to fit, thus forming a hinge or pivotal connection between said plate and arm. At the opposite end of the trammelhead is a downwardly-depending screwthreaded rod 12, which passes through an aperture in the end of plate 9 and is provided with a screw-threaded adjusting-nut 13, bearing against the under side of plate 9 and by which it may be adjusted. Interposed between the trammel-head and plate 9 is a spring 14., which presses said plate down upon the adj usting-nut.

The operation of the device will be readily understood. The trammel-head 2 is moved or slid along the beam until it approximately reaches the point desired. It may now be adjusted with great precision by turning the nut in the desired direction. By turning the nut one way the plate 9 will be depressed by the spring 14, causingthe point which is connected with it to be moved in a corresponding direction. By reversing the movement of the nut the end of plate 9 will be elevated,

thus reversing the direction of movement of the trammel-point, as will be obvious.

The trammel-head 3 may be of the ordinary construction, or it may be similar to head :2,

if desired. It will also be understood that the point illustrated in the drawings may be replaced by a pencil-point when desired.

Having thus described my invention, what I claim is v 1. The combination, with a beam, of a horizontally-movable trammel-head, a spring-actuated point carrying plate pivotally connected therewith, and a screw-threaded rod secured to said head and passing through an aperture in said plate, substantially as described.

2. A trammel-headhavingadependingarm 6, provided with two outwardly-projecting lugs 7 at its lower end, a point-carrying plate 9, recessed at one end so as to form two shoulders 10, a screw-rod depending from the under side of the trammel-head,passing through an aperture in the plate 9, and provided with an adjusting-nut 13, and aspring 14, interposed between plate 9 and the under side of the head, substantially as described.

In testimony that I claim the foregoing as my own I have hereunto affixed my signature in presence of two witnesses.

SILAS E. SELLECK.

Witnesses:

W. W. RoBsoN, W. H. MULLINS. 

